The importance of controlling the immune response to cancer is underscored by observations that different types of tumors are affected differently by humoral and cell-mediated immunity. The concomitant injection of antigen and antibody can affect the immune response both qualitatively and quantitatively. The type of modification obtained appears to be dependent on the time, type and the amounts of antibody injected relative to the antigen. The objective of the proposed study is to establish the conditions under which the cellular and humural responses to tumor specific antigens can be either potentiated or suppressed by the passive introduction of specific antibody. In this study, mice (DBA/2 or BNL/T) will be injected with different combinations of mouse anti-L1210/MTX and L1210/MTX cells, and the magnitude of the immune response (cellular and humoral) elicited will be determined. Based on the results obtained the regimen of injections will be changed in an attempt to potentiate the cell-mediated immune response while concomitantly suppressing the humoral immune response. The efficacy of skewing the immune response so that it is predominantly cell-mediated will be tested in mice carrying solid tumors produced by L1210/MTX subcutaneous or intramuscular inoculation.